مقايسه استحكام شكست دندان هاي مولرشيري پالپوتومي شده پس از ترميم با كامپومروكامپوزيت

Introduction: Maintenance of primary teeth has a special importance for development of occlusion and arc stability. Primary teeth which have lost a lot of tooth structure are restored routinely with stainless steel crowns.Bonded restorations reinforce the remnant structure of tooth and increase the fracture strength. The purpose of this study was to determine the fracture strength of pulpotomized primary molars after restoring with Coremax II and Compoglass. Materials & Methods: In this parallel in vitro interventional study, 60 extracted second primary molars, were selected. After the teeth were mounted in self-curing acrylic resin, the standard pulpotomy was performed. The teeth were divided into 3 groups of 20. Group A was restored with Coremax II, group B with Compoglass and group C (control) with amalgam. All groups were subdivided into 2 subgroups for load cycling Subgroups A, , B, and C1 were regarded as base without load cycling. Subgroups A, , B2 and C2 were loaded for a period of 5 days load cycling. After that, specimens were placed in Incubator for 24 hours. Finally all groups were fractured in the Instron Machine. compressive test was performed with the round Cross head speed of 5-mm/min. All specimens were examined for type of fracture (adhesive, cohesive) with use of a steriomicroscope (x16). Quantitative data analysis was done using ANOVA and Duncanʹs test with a 95% significance level. Chi-square test was performed for evaluation of kind of fracture. Results: There was an interaction between two factors of time and material (P<0.05). The time interval had a significant effect on mean fracture strengths of Coremax II and amalgam (P<0.05). The most fracture strength was observed at base line. Kind of material had a significant effect on fracture strength. At baseline, Compoglass had the least mean fracture strength (97.19 kg) and Coremax II had the greatest one (131.39). After 5 years there was no significant difference in fracture strength between amalgam and Compoglass, but the fracture strength of Coremax was significantly higher than the others (P<0.05). There was a correlation between kind of fracture and material. In amalgam, 100% of fracture was of adhesive and in Compoglass, 60% of cohesive type while in Coremax II, 85% of the fracture was of adhesive type., Conclusion: According to this study and because of high fracture strength of teeth restored with Core max II, this material is an acceptable restoration material just for restoration of pulpotomized primaryolars.